Resolver apparatus using variable capacitors comprising toothed rotor and stator

Claim 1

APPARATUS FOR PROVIDING A SIGNAL HAVING A FREQUENCY EQUAL TO THE DIFFERENCE BETWEEN ONE SIGNAL FREQUENCY AND A MULTIPLE OF ANOTHER SIGNAL FREQUENCY COMPRISING A STATOR HAVING TWO CONDUCTIVE CIRCUMFERENTIALLY ALIGNED SECTIONS OF N SYMMETRICAL TEETH AND TWO OTHER CONDUCTIVE SECTIONS, SAID FOUR SECTIONS BEING ELECTRICALLY INSULATED FROM EACH OTHER AND EACH BEING ADAPTED TO HAVE APPLIED THERETO AN ELECTRICAL SIGNAL, AND A ROTOR SUPPORTED FOR RELATIVE ROTATION ABOUT THE STATOR LONGITUDINAL AXIS AND PROVIDED WITH FOUR CONDUCTIVE SECTIONS ALL ELECTRICALLY CONNECTED TOGETHER, TWO SECTIONS OF SAID ROTOR HAVING N SYMMETRICAL TEETH AXIALLY ALIGNED WITH RESPECTIVE TEETH SECTIONS ON THE STATOR, SAID ROTOR TEETH SECTIONS BEING CIRCUMFERENTIALLY DISPLACED WITH RESPECT TO EACH OTHER ONE HALF THE WIDTH OF A TOOTH, AND THE OTHER SECTIONS OF SAID STATOR AND ROTOR BEING SO DISPOSED THAT AT LEAST ONE SECTION OF EACH PAIR OF CORRESPONDING STATOR AND ROTOR SECTIONS IS SUBSTANTIALLY SMOOTH SURFACED, WHEREBY TWO VARIABLE CAPACITANCES AND TWO CONSTANT CAPACITANCES ARE PROVIDED, SAID VARIABLE CAPACITANCES BEING RESPECTIVELY VARIED SINUSOIDALLY AND COSINUSOIDALLY N TIMES FOR EACH COMPLETE TURN OF SAID ROTOR, AMPLIFIER MEANS THE INPUT AND OUTPUT OF WHICH ARE CONNECTED RESPECTIVELY TO STATOR SECTIONS NOT DISPOSED TO PROVIDE VARIABLE CAPACITANCES, MEANS ADAPTED TO APPLY TO SAID STATOR SECTION DISPOSED TO PROVIDE A SINUSOIDALLY VARYING CAPACITANCE A SIGNAL THAT VARIES SINUSOIDALLY AT A FIRST FREQUENCY, MEANS ADAPTED TO APPLY TO SAID STATOR SECTION ADAPTED TO PROVIDE A COSINUSOIDALLY VARYING CAPACITANCE A SIGNAL THAT VARIES COSINUSOIDALLY AT SAID FIRST FREQUENCY, WHEREBY THE OUTPUT SIGNAL FROM SAID AMPLIFIER MEANS IS PROVIDED WITH A FREQUENCY EQUAL TO THE DIFFERENCE BETWEEN SAID FIRST FREQUENCY AND N TIMES THE FREQUENCY AT WHICH SAID ROTOR IS ROTATED.